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D. B. HUTTON & A. P. G. DANIELS. DRILL FOR DRILLING SQUARE-HOLES. No. 456,258. Patented July 21, 1891.

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D. B. HUTTON 8v A. F. G. DANIELS. DRILL FOR DRILLINGSQUARE HOLES.

No. 466,258. Patented July 21; 1891.

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1). B. BUTTON & A. F; G. DANIELS.

DRILL FOR DRILLING SQUARE HOLES.

No. 456,258. Patented July 21,1891.

7' Jamie. gm. wz. .73 A jxagmuh UNITED STATES PATE T OFFICE.

DAVID BROIVN HU'ITON AND AROHIBALD FREDERICK GEORGE DANIELS, OF ESSEX, ENGLAND.

DRILL FOR DRILLING SQUARE HOLES.

SPECIFICATION forming part Of Letters Patent N0. 456,258., dated July 21, 1891. Application filed February 3, 1891- Serial No. 380,105. (No model.)

To all whom it may concern:

Be it known that we, DAVID BROWN HUT- TON and AROHIBALD FREDERICK GEORGE DANIELS, subjects of the Queen of Great Brit-. ain, residing at Essex, England, have invented new and useful Improvements in and Connected with Drills for Drilling Square Holes, of which the following is a specification.

This invention relates to drills which may be applied to drilling-machines, lathes, and the like for drilling square holes, the said drills being of triangular or substantially triangular shape in transverse section, but having their sides slightly curved or rounded, and having a single cutting-edge extending across the end of the same and used in combination with a guide-plate having a square hole.

In the accompanying drawings, Figure 1 is an elevation of a drill constructedaccording to our invention, and Fig. 2 is a view of the same in a position at right angles to that shown in Fig. 1. Fig. 3 is a View of the cutting end of the said drill; and Fig. at is a section on the line 5c 00, Fig. 2. Fig. 5 is the view of the guide-plate. Figs. 6 and 7 are a side and front elevation, respectively, illustrating the application of our improved drill to an ordinary vertical spindle drilling-machine; and Figs. 8 and 9 are side and front views illustrating a modification.

Similar letters of reference indicate corresponding parts in the several figures.

a indicates our improved drill, one end of which is of cylindrical shape, as shown, or otherwise suitably shaped to fit the socket of the drilling machine, lathe, or the like in which it is to be used, while the lower art or shank, which is of triangular shape, but with slightly-rounded sides, as hereinbefore stated, is made of any desirable length, according to requirements. These rounded sides are found in practice to have a very decided advantage,

as they prevent a considerable amount of jarring which takes place when a fiat-sided drill is employed. The end of the triangular shank is ground or beveled off toform one or more cuttingedges, but in such a manner that the drill shall have no central point upon which it can rotate.

As shown in Figs. 1 to 3, the drill may be provided with the cutting-edge b on one of the triangular sides and with another cuttingedge 0 at right angles thereto, the latter being formed by notching the other two sides of the triangular shank, as shown at d d. The halves of the edge I) are beveled in opposite directions, as indicated most clearly in Fig.2

. at e e, and the edge a is also beveled in such a manner that during the rotation of the drill itwill cut with the other edge. In some cases the edge 0 is dispensed with, in which case the whole of the cutting is effected by the edge I).

f is the guide-plate through which the drill works,the said guide-plate being provided with a square hole g, the sides of which are of slightly-greater length than the sides of the triangular shank, the result of which arrangement is that when the drill is rotated in the hole in the guide-plate the angles of the saiddrill will be caused to enter the angles of the said hole, and thus insure the cutting out of the whole surface exposed inside the hole. This guide-plate may be fixed to the table of a drilling-machine or attached to the rest of a lathe or to the article to be drilled; or it may be carried by brackets h h, bolted to the frame of the drilling machine, as indicated in Figs. 6, 7, 8, and 9. It is obvious that when rotating in the hole of the guide-plate the drill will have no central point, and it is therefore necessary to provide-for a slight lateral play of the drill. tageously accomplished either by allowing the drill to fit loosely in the socket of the drillingmachine spindle or by mounting the drill in an independent socket carried upon the drillspindle by means of a universal joint, as shown in Figs. 8 and 9. In this latter case, however, the guide-plate f is made of greater depth than that hereinbefore described, (for instance, in the manner shown in the said Figs. 8 and 9,) so as to hold the drill at two points in its length.

Although we have described our improved drill as applied for drilling square holes, it is obvious that if the drill is used without the guide and is rigidly fastened in the socket of the drilling-machine it will drill round holes.

This may be advan-' The curved or round form of the sides of the triangular-drill shank is shown in dotted lines in F1 l.

Having 110W particularly described and as- 5 certained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is- 1. A triangular drill having-rounded sides and having a single cutting-edge extending 10 across and biseeting theend of the same.

2. In combination with a drill-soeket havin; a universal joint, a triangular drill having rounded sides anda cutting-edge extending across the end of the same.

DAVID BROWN llU'lTON. ARCHIBALD FREDERICK GEORGE DANIELS.

\Vitnesses:

JOHN E. BoNsFIELD, Of the firm of G. F. Redf'ern d; (70., 4; South S'freet, l insbary, London, Patent Agents.

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